Mechanical interlock for electric switches

ABSTRACT

An inexpensive thermoplastic interlock member which spatially aligns, anchors and mechanically interlocks the operation of a pair of electrical relays. The interlock is a compact one piece member comprising a frame, anchorage means for anchoring the frame between two relay assemblies, each relay assembly having a respective armature, and an interlock element suspended within the frame by an integral flexible link for movement laterally of the frame, to prevent simultaneous actuation of the relay armatures. The interlock element has inclined surfaces extending laterally of the frame and into the paths of movement of the two armatures so that the interlock element is laterally displaced to obstruct the path of movement of one armature whenever the other engages the inclined surface thereof.

United States Patent 191 Kolb et al.

[11] 3,824,510 July 16, 1974 MECHANICAL INTERLOCK FOR ELECTRIC SWITCHES 75 Inventors: Arthur F. Kolb, Mequon; John J.

Gilmore, Grafton, both of Wis.

[73] Assignee: Cutter-Hammer, Inc., Milwaukee,

Wis.

[22] Filed: July 19, 1973 [21] Appl. No.: 380,564

[52] US. Cl. 335/160, 200/50 C [51] Int. Cl. H0111 9/26 [58] Field Of Search 335/160; 200/50 C [56] References Cited UNITED STATES PATENTS 3,510,612 5/1970 Ward 200/50 C 3,592,985 7/1971 Arnesberg 200/50 C Primary Examiner-Harold Broome Attorney, Agent, or Firm-Hugh R. Rather; Wm.

Autio 57 ABSTRACT I An inexpensive thermoplastic interlock member which spatially aligns, anchors and mechanically interlocks the operation of a pair of electrical relays.

The interlock is a compact one piece member comprising a frame, anchorage means for anchoring the frame between two relay assemblies, each relay assembly having a respective armature, and an interlock element suspended within the frame by an integral flexible link for movement laterally of the frame, to prevent simultaneous actuation of the relay armatures.

The interlock element has inclined surfaces extending laterally of the frame and into the paths of movement of the two armatures so that the interlock element is laterally displaced to obstruct the path of movement of one armature whenever the other engages the inclined surface thereof.

2 Claims, 6 Drawing Figures mama JUL 1 e um SHEEI 2, 0F 2 MECHANICAL INTERLOCK FOR ELECTRIC SWITCHES BACKGROUND OF THE INVENTION This invention relates to electrical switching apparatus and the like, and more particularly to improvements in mechanical interlock devices for preventing simultaneous actuation of both armatures in a pair of adjacent electromagnetic relay devices.

A typical usage of relay apparatus is to connect motor windings of either a two speed or reversible motor directly across the power lines, and consequently, means must be provided to preclude simultaneous closing of the individual relays. Hence, it is a requirement that such relays be positively interlocked to prevent the completion of a circuit through more than one relay at any given instant.

Various mechanical interlock devices have been devised for performing this function, and although such devices have generally served their purpose, no single device has proven entirely satisfactory from a cost, assembly and operational standpoint.

For example, some prior interlock devices are bulky in size utilizing a large number of parts which results in complicated mechanism to perform the interlocking function. Such designs are generally costly to manufacture and susceptable to failure. Moreover some of these devices have exposed mechanism, which may be easily defeated and which may also be a possible electrical shock hazard.

More recently, mechanical interlocking devices having fewer parts and being smaller in size have appeared which tend to alleviate some of the aforementioned problems however, they too have not been entirely satisfactory in that they utilize loose parts that make them difficult to assemble and anchor to adjacent relay elements. Consequently, these newer devices require much care and assembly time to ensure that simultaneous trip and reset of the separate relay functions is obtained. Moreover, these newer devices have interlocking elements which are required to bend or pivot in a compressive manner and consequently they tend to become less reliable with age and use as'the interlocking element fails to rebound to the neutral position and will remain in one blocking position at all times.

SUMMARY OF THE INVENTION The general object of the present invention is to provide an improved mechanical interlock of the type described which circumvents the problems heretofore noted as well as other disadvantages of the prior art.

More specifically it is an object of this invention to provide a mechanical interlock for relay apparatus and the like which is capable of manufacture at low cost, is of one-piece construction and so designed to be readily and easily assembled in mass production operation and yet yield reliable performance after millions of operations.

An additional object of the present invention is to provide a mechanical interlock device which spatially aligns and anchors two adjacent relay devices without the need for a common support bracket for mounting the relays.

Another object of the instant invention is to provide a mechanical interlock which is so constructed that its application to associated relay apparatus requires no.

dismantling of any of the apparatus or alteration in its design or construction.

A further object of the present invention is to provide a mechanical interlock which affords ready and free movement of various associated movable parts and which requires negligible effort to cause interlocking action between such parts.

A still further object of the invention is to provide a tamper proof mechanical interlock for relay apparatus.

DETAILED DESCRIPTION OF THE DRAWINGS In describing the present invention, reference will be made to the accompanying drawings forming a part of the instant invention wherein:

FIG. 1 is a front elevational view of the one piece mechanical interlock constructed in accordance with the instant invention.

FIG. 2 is a sectional view taken along line 2-2 of the mechanical interlock shown in FIG. 1.

FIG. 3 is a diagrammatic side view of two adjacent electromagnetic relay apparatus embodying the mechanical interlock of the present invention.

FIG. 4 is a front elevational view showing the mechanical interlock of the instant invention illustrating analternate anchorage arrangement therefor.

FIG. 5 is a sectional view taken along line 55 of the mechanical interlock shown in FIG. 4.

FIG. 6 is a side view of two adjacent electromagnetic relay apparatus embodying the mechanical interlock shown in FIGS. 4 and 5.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS. 1 and 2 of the drawings, the interlock member of the present invention is shown comprising a frame 10 in which a pair of interlock elements 12 and 14 are suspended by a flexible link 16. Further included are outward extensions 18 and 20 of the frame 10 which support hooks or anchorage elements 22, 24, 26 and 28 for anchoring adjacent relay assemblies.

The frame 10 comprises a peripheral rib 30 surrounding a web 32 and leaving an aperture 34 disposed centrally in the upper portion of the frame 10 and as seen in FIG. 1, the aperture 34 accommodates the link 16 and interlock elements 12 and 14.

The link 16 is in the form of a thin strap or web connecting the interlock elements 12 and 14 to the upper part of the frame 10 and is freely bendable to permit displacement of the interlock elements 12 and 14 laterally of the frame and perpendicular to the plane of the paper in FIG. 1.

The upper edges of the interlock elements 12 and 14 are curved and present inclined surfaces adjacent the link 16. These surfaces are engageable by the armatures 36 and 38 of the relay elements 40 and-42 when the interlock member is installed between the relay ele ments 40 and 42 as shown in FIG. 3.

With the interlock member installed between the relay elements 40 and 42, the anchorage elements 22 to 28 engage in complementary recesses 52 and 54 respectively in the relay elements 40 and 42 to retain the frame 10 in position between the two relay elements. Facing side walls of the relay elements 40 and 42 abut the rib 30. The interlock elements 12 and 14 project into the paths of movement of both armatures 36 and 38 when the relay elements are de-energized. If one of the armatures is actuated, as shown for the armature 'since the interlock elements 12 and 14 obstruct its path of displacement since the interlock elements will be An alternate anchorage arrangement for the mechan- 'ical interlock of the present invention is shown in FIGS.

4-6 which utilize like reference characters for like parts hereinbefore described. The arrangement provides for an additional extension 70 on frame for supporting anchorage elements 72 and 74 to ensure proper alignment of the mechanical interlock relative to relay elements 76 and 78 regardless of any mounting surface irregularities. For this purpose it is to be noted that extension 70 is positioned laterally of frame 10 and generally above interference elements 12 and 14, and that in such position, elements 72 and 74 thereon engage in complimentary recesses 90 and 92 in relay elements 76 and 78 and cooperate with elements 22, 24, 26 and 28 therebelow, to achieve optimal spatial alignment between the relay elements should they be mounted on an uneven surface. It is to be further noted that an additional extension (not shown) could be positioned on the left side of frame 10 directly opposite extension 70 to even further ensure proper alignment between the respective parts. As is readily apparent, these alternate anchorage arrangements enhance the stability of performance of the mechanical interlock disclosed hereinbefore.

Thus, it will be apparent to those skilled in the art, that the present invention provides a substantial improvement in reducing the number of component parts for mechanical interlocks for relay type and other switching devices. It will also be readily recognized that such reduction of parts coupled with the unique arrangement of the interlock and anchorage elements maintained in this position by the side of the armature provides a highly efficient and durable switch which is inexpensive to manufacture and readily adaptable to existing relay assemblies without the need for extensive or expensive modifications to the relay housing or internal component parts. 1

While the interlocking member hereinbefore described is effectively adapted to fulfill the objects stated, it is to be understood that the invention is not intended to be confined to the particular preferred embodiment disclosed or for use solely with electrical contactor devices, inasmuch as it is adaptable for use with other relay and swit'ching'devices and is susceptible of various modifications without departing from the scope of the appended claims.

. We claim:

1. A mechanical interlock for use with a pair of switching devices having movable actuating members arranged for parallel recipricatory movement and comprising a one piece molded member having a frame portion with an opening extending therethrough an integral flexible link extending from one end of said opening partially across the latter, interlock portions formed on said link adjacent its free-end and engageable by a movable actuating member of one of said switching devices to be moved outwardly-of said opening into blocking relation to the path of movement of the actuating element of the other of said switching devices and vice versa, and integral hook portions extending from opposite sides of said frame portion for interlocking engagement within the housings of an adjacently mounted pair of said switching devices to provide fixed positioning of said frame portion between said switching devices.

2. A mechanical interlock according to claim 1 wherein said interlock portions have like semi-circular contoured surfaces extending from opposite sides of said link for engagement respectively with the movable actuating members of an associated pair of switching devices. a 

1. A mechanical interlock for use with a pair of switching devices having movable actuating members arranged for parallel recipricatory movement and comprising a one piece molded member having a frame portion with an opening extending therethrough an integral flexible link extending from one end of said opening partially across the latter, interlock portions formed on said link adjacent its free-end and engageable by a movable actuating member of one of said switching devices to be moved outwardly of said opening into blocking relation to the path of movement of the actuating element of the other of said switching devices and vice versa, and integral hook portions extending from opposite sides of said frame portion for interlocking engagement within the housings of an adjacently mounted pair of said switching devices to provide fixed positioning of said frame portion between said switching devices.
 2. A mechanical interlock according to claim 1 wherein said interlock portions have like semi-circular contoured surfaces extending from opposite sides of said link for engagement respectively with the movable actuating members of an associated pair of switching devices. 